Diabetes is a disorder of metabolism in which either the pancreas produces too little or no insulin, or the body cells do not respond to the insulin that is produced. In type I diabetes, the pancreas does not produce any insulin. In type II diabetes, also known as adult onset diabetes, there are two potential problems: the pancreas produces too little insulin, or the body cells do not respond to the insulin that is produced. In either scenario, the glucose cannot efficiently move from the blood to the cells, which leads to a buildup of glucose in the blood and an overflow into the urine. As a result, the body loses its main source of fuel. Administering insulin or oral antihyperglycemic agents allows the glucose to enter the cells more efficiently, thus providing a source of fuel.
Pioglitazone is an oral antihyperglycemic agent that acts primarily by decreasing insulin resistance. Pharmacological studies indicate that pioglitazone improves sensitivity to insulin in muscle and adipose tissue and inhibits hepatic gluconeogenesis. Pioglitazone improves glucose resistance while reducing circulating insulin levels.
Pioglitazone is currently marketed as ACTOS®. Pioglitazone hydrochloride has the chemical name [(±)5-[[4-[2-(5-ethyl-2-pyridinyl)ethoxy]phenyl]methyl]-2,4-] thiazolidinedione monohydrochloride. (CAS Registry No. 111025-46-8.) The chemical structure of pioglitazone is shown as Formula I.

U.S. Pat. No. 5,585,495, incorporated herein by reference, discloses methods for the synthesis of pioglitazone.